Did they rename the Fast Jacket the Running Jacket or something? As far as the Flak, it IS a pain to swap lenses, but for running I don't usually change the lenses, either it's bright enough out for VR28 or I don't bother wearing them. I find that the frame does work well for running though. Stays put, doesn't fog a lot, etc.

And it's actually not hard to remove lenses. You just need to know how to flex the frame. I will say that if you plan to swap lenses very frequently, you may want to opt for a frame with the switch lock mechanism (Radar Lock, Fast Jacket, Split Jacket, Jawbone/Racking Jacket). Frequent lens changes on the Flak Jacket will wear the mount points on the lens and the frame over time. I have both a Flak Jacket and a Half Jacket and they both feel kinda loose as i've swapped lenses on each of these frames over the years. They're not loose, but definitely not as tight as they used to be.